Antitheft electric-light bulb



"Dec. 10, 1929. s. F. BASHARA- ET L ANTITHEFT ELECTRIC LIGHT BULB Fil m1925 3 Sheets-Sheet 1 & S-F-BMBhQLWL ra /mm Dec. 10, 1929. 51 F. BASHARAET Al. 1,738,583

ANTITHEFT ELECTRIC LIGHT BULB Filed June 22, 1925 2 Sheets-Sheet 2Patented Dec. 10, 1929 UNITED ST T E S OFFICE AN'IITHEFT ELECTRIC-LIGHTBULB Application filed. June 22,

Our invention relates to an improvement in electric lamps, and pertainsmore particularly to the means of attachment between the electric bulband the socket into which it is secured.

It is an object of the invention to provide an attachment of the bulb inthe socket which will be theft proof. It is desired to form an electricbulb which may be readily attached within its socket but which cannot bereadily detached without special means, or without special knowledge ofthe construction of the device. It is desired to construct the bulb 1nsuch manner that it may be attached in any ordinary lamp socket andwhich may be manufactured cheaply in'quantities, and at the same timenot liable to be detached or stolen.

In accomplishing the results above stated,

the invention pertains largely to details of construction andarrangement of parts which will be more particularly described.

Referring to the drawing herewith, Flg. 1 is a side elevation of anelectric light bulb, certain parts thereof being broken away for greaterclearness, and showing a broken section of the lamp socket in centralvertical section. Fig. 2 is a longitudinal section of the lamp socketshowing the improved bulb secured therein, the parts being in adifferent position from that shown in Fig. 1. Fig. 3

is a transverse section on the plane 33 of Fig. 1. Fig. 4 is a sideelevation of an electric light bulb illustrating a slightly differentembodiment of the invention, the socket and the attachment means beingshown in longitudinal section. Fig. 5 is a view of the upper end of thebulb showing the parts in a position different from that shown in Fig.4.

Fig. 6 is a transverse section on the plane 6 6 of Fig. 4. Fig. 7 is aside view of an electrlc light bulb employing a slightly diflerentembodiment of the invention, the upper shank and shell of the devicebeing shown in vertical section. Fig. 8 is a side elevation of the upperend of the construction shown in Fig. 7. Fig. 9 is a transverse sectionon the plane 9-9 of Fig. 7. Figs. 10 and 11 are front and sideelevations respectively of the 50 Wrench which may be employed inattaching 1925. Serial No. 38,875.

and detaching a bulb with the socket. Fig. 12 is a side elevation of theshank of a bulb showing a still different means of connecting the shankof the bulb with the shell, and Fig. 13 is a transverse section on theplane 13-13 66 of Fig. 12.

In the embodiment of our invention, shown in Figs. 1 to 3 inclusive, thebulb shown is an ordinary electric light bulb having an up er shank 1,of glass-or other electrically ins ating' material, secured to the bulb2 in the usual manner. There is mounted upon the shank of the bulb acovering, or cap, 3 of metal or some other conducting materialcylindrical in shape and fitting tightly about 5 the shank of the bulb.It has at its upper end a'radial flange 4 making contact at its outeredge with a shell 5 formed with a coarse thread thereon toengage withinthe metallic socket 6 of ordinary construction.

Adjacent the lower end of the covering, or cap, 3 is provided acorrugated or toothed. portion 7, formed in the metal of the cap andcomprising one or more teeth which form one member of a clutch. Thelower end of the shell 5 is turned inwardly to contact with the shell.It has on the inwardly turned portion 28 a plurality of indentations, orrooves, 8 to receive the teeth 7 formedon t e bulb cap. These'teeth 7and 8, forming the clutch 30 or engaging members between the cap and theshell of the base cap, are held normally out of engagement by means of aspring 9. This spring is spiral in shape, the lower end of which isseated upon the lower portion 28 35 of the shell and the upper end ofwhich bears against the flange 4 of the cap. It thus serves to force theshank of the bulb upwardly in the shell maintaining a bulb rotatablerelative to the shell.

At the upper end of the socket 6 there is a U-shaped contact member 10adapted to close the electric circuit between the conducting wire 11 andthe upper end.12 of the filament within the bulb. We contemplate thatthis contact member may be made to also serve as a spring to take theplace of the spring 9 by constructing the'contact member as shown inFigs. 4 to 6 inclusive. In this embodiment, the shank and the'shell'andthe socket are formed as in the previous embodiment. At the upper end ofthe shank, however, we connect a spring contact member 14 which servesthe purpose of the other contact member 10, and also serves to force theshank 1'-. downwardly relative to the shell 5 furthermore there is aridge 15 formed upon the shell 3' ada ted to fit against the lower end28 to limit the ownward movement of the shank relative to the shell 5.In this embodiment the corrugation or teeth 7 upon the cap are formedbelow the inwardly turned end 28 of the shell so that the bulb will haveto be moved upwardly instead of downwardly to engage the teeth 7 withthe teeth formed within the end 28 of the shell.

In operating the invention thus disclosed, the bulb with the shank 1 andthe cap 3 will be drawn downwardly in the Fig. 1 embodiment to engagethe teeth 7 within the teeth 8 of the shell. The two parts will be thusheld against relative rotation and the shell.

may be thus rotated to screw it within the socket 6 in the usual manner.When the bulb has thus been secured in the socket. the same may bereleased and the spring 9 will then act to force the shank of the bulbupwardly in the shell 5 so that the bulb may be rotated withoutaffecting the screwing or unscrewing of the shell from the socket. Vhenit becomes desirable to release the bulb from the socket, this may bedone by drawing the bulb downwardly within the shell engaging the teeth7 and 8, thus making it possible to rotate the shell and unscrewing thesame from the socket.

In the Fig. 4 embodiment, the bulb will have to be pushed inwardlyrelative to the shell 5 in order to engage the teeth 7 and 8 so as torotate the shell with the bulb. In this manner the bulb may be screwedwithin the socket in the usual manner and, when fully engaged, thespring 14 forming the contact, will bear against the upper end of thesocket tending to force the shank and the bulb, outwardly releasing theteeth 7 from their engagement with the shell and allowing rotation ofthe bulb relative to the shell and the socket.

It is believed that as the means of engaging the shell and the cap ofthe bulb non-rotatably together is hidden from the ordinary thief, itwill serve the purpose of making the bulbtheft proof, for the ordinarythief will rotate the bulb, and, as the clutch formed by the teeth 7 and8 is out of engagement the bulb cannot be released. This can only bedone by a proper understanding of the manner in which the bulb and theshell can be engaged in the manner described.

In Figs. 7 to 11 inclusive is illustrated a third embodiment of theinvention wherein the bulb can only be unscrewed from the socket by theuse of a detachable member or wrench. To accomplish this purpose, the

upper shank 1' of the bulb is formed with a cap 3" substantially as thatshown in Fig. 4 except that the upper end is curved inward- 1y about theupper insulated portion 16 of t 1e shank. There is formed on one side ofthis cap, adjacent the lower end, a corrugated section 7" forming teethsimilar to those shown in Figs. 1 to 6. The shell 5" is fitted over theouter face of the cap and is rotatable thereon in its normal position.The lower end of the shell is curved inwardly into contact with the capand has at one point a eries of corrugations or teeth8 which may bebrought by rotation into position adjacent the corrugations 7 as shownin Fig. 9. It will be seen that the shell will be rotatable upon theshank of the bulb at all times except when a wrench is inserted betweenthe toothed portion 7 and 8". Such a wrench is shown in Figs. 10 and 11.It is formed of a short handle 17 having a curved blade 18 thereon,which is corrugated as shown in Fig. 10, to fit between the shell andthe cap, as shown in Fig. 7. When thus inserted, the wrench acts to lockthe shell to the ca so that when the bulb is rotated the shell will alsobe rotated to secure the bulb within the socket. -When the bulb is thussecured in position, the wrench may be withdrawn and the bulb will befree to rotate relative to the shell and the socket.

The connection between the bulb cap and the shell may be varied invarious ways coming within the spirit of our invention, and in Figs. 12and 13 amodified form is shown. In this embodiment, the cap is formedwith a longitudinal groove 19 therein, and the shell is formed with agroove 20, the groove 20 extending outwardly while the groove 19 extendsinwardly relative to the shank of the bulb. To engage the cap with theshell in this embodiment, a small rod or pin 21 may be employed, andwhen said pin is in serted within the grooves 19 and 20, it will serveto lock the shell and the cap together so that the shell will be rotatedwith the rotation of the bulb.

It will be noted that in all of the embodiments of the invention shownand described, the bulb will be rotatable normally within the shellwhich makes engagement with the lamp socket. In each case the shank ofthe bulb may be engaged with the shell to rotate therewith by meansmanually controlled by the operator. In each case the connection betweenthe shank of the bulb and the shell may be likened to a lock, which maybe in the form of a combination lock or one involving the use of a key.Figs. 1 to 6 inclusive, there-.

fore, illustrate the combination lock and these bulbs can only bedetached after once being secured within the socket by one knowing thecombination. In the embodiments illustrated in Figs. 9 to 13 inclusive,the bulb can only be detached from the socket by the use of a keyserving to secure the bulb within the shell.

While these forms of attachment of the bulb to the socket will not beabsolutely theft I proof, they will resist attempts of ordinary patronsof hotels, or other public places, from taking the bulbs from thesockets and appropriating them. Only those knowing the means whereby thebulbs may be detached will be able to remove the bulbs when desired. Thefurther advantages of this inventive idea will be apparent to thoseskilled in the art. What We claim as new and desire to protect byLetters, Patent is:

1. In an electric lamp, a bulb, a shank thereon, a cap thereon, athreaded shell normally rotatable on said cap, co-operating teeth onsaid cap and shell, and means adapted to be inserted between said teethto connect said teeth whereby said cap and shell are held againstrelative rotation.

2. In an electric lamp, a bulb, a shank thereon, a threaded shell onsaid shank and normally rotatable thereon, and means insertible betweensaid shell and said shank to secure them together, so that the rotationof said bulb will cause the rotation of said shell therewith.

3. In an electric lamp, a bulb, a shank thereon, a cap on said shank, athreaded shell on said cap, said shell being normally rotatable withrespect to said cap, and manually operable means adapted for temporaryin sertion between said cap and said shell whereby rotation of said bulbwill cause rotation of both said cap and shell.

4. In an electric lamp, a bulb, a shank thereon, a cap fixed on saidshank, a threaded shell normally rotatable with respect to said cap, andmeans adapted to 'be engaged between said cap and shank whereby saidshell may be moved by rotation of said bulb.

5. In an electric lamp, a bulb, a. shank thereon, a threaded shellnormally free to rotate on said shank, opposed spaced surfaces on saidshank and s ell, and independent means adapted for temporary insertionbetween said shank and shell whereby said shell may be rotated with saidshank.

n testimony whereof we hereunto aflix our signatures this 16th day ofJune, A. D.,

SAMUEL F. BASHARA. JAMES w. GAIN.

